I usually look at what I want in a dungeon and select classes accordingly, also factoring in quirks.
My sister just brings Vestal - Plague Doctor - Hound Master - Man-at-Arms everywhere and destroys everything.

Yeah I don't understand people who watch horror movies either. /s
The game is easy enough already, and a lot of people like the challenge.

I don't think it's bad to mod your game to hell, even if it kinda ruins it.
I wouldn't do it myself, but there is no harm done if it's a single player game.

On the other hand, complaining when you have ridiculously OP characters on display might rile up quite a few people. They feel like they worked harder to get the same achievements, following the rules, while they see you as a cheater. And nobody likes cheaters.

If you don't enjoy the combat, I don't think you will have much fun, however if you just find it too easy, you could always play on the highest difficulty and/or imposing restrictions on yourself (like not using torches), and trying out weird party compositions.

There is plenty decision making in the game, you just haven't experienced bad luck or seen the bosses/minibosses/events/higher lvl enemies yet. Your whole party can be easily destroyed, if you don't bring a team and choose abilites that's suitable for the fights.(of course that's easily fixed by reading the wiki, but I think that ruins the experience)

I was still using a 21 inch EIZO CRT that could do 100 hz on 1600x1200 in 2007.
We bought it in 2004 in a second hand electronics shop for like 40$ on sale.
It was really heavy, but switching from a 17 inch 75hz to that was mind blowing.

I prefered the CRT to my school's shitty TFTs, which gave me a headache.

Oh, so you are questioning the validity of the "speedrun"? I think that's a fair point actually.
I just wanted to give a general answer, because the question seemed genuine and not about "cheating".

Personally, I think it's fine to mod your game as much as you like, since it's single player. He could've modified some files without anyone noticing. In my opinion the video is still good even if there is "cheating" involved. It certainly diminishes the achievement, but you can clearly see the heroes and trinkets used in his videos, and everyone can try the challenge for themselves.